Mechanically expanded packer



Jan. 11, 1955- Q sw -r 2,699,214

MECHANICALLY EXPANDED PACKER Fmd Sept. 13. 1949 Y 2 Sheets-Sheet 1 CZ'C/L 6. SWEET I INVENTOR.

United States Patent MECHANICALLY EXPANDED PACKER Cecil H. Sweet, Hobbs, N. Mex., assignor to Sweet Oil Well Equipment, Incorporated, a corporation of New Mexico Application September 13, 1949, Serial No. 115,352

4 Claims. (Cl. 166-199) This invention relates to oil well packers and more particularly to the type of such packers as are usually set by distorting the rubber packing element by pressure.

It is well known in the art that when packers of this type are run into the well and pressure is applied to the ends of the rubber the distortion occurs at or near the end which receives the pressure from the moving member. This usually occurs at the top of the rubber since the lower member supporting the packer is customarily associated with the slips or a tail pipe the function of which is primarily to limit or prevent further downward movement of the packer assembly. The result is the movement by sliding or friction contact of the previously set portion of the packer along the well bore or casing as downward pressure progresses from the supporting pipe string until the operator stops the proceeding. Heretofore most packers so set or treated have been torn or ruptured from these actions and have frequently been most diificult to retrieve from the well upon completion of the service operation for which they were intended. Also quite generally, only the upper portion of the packer is distorted into set position while the lower portion remains undistorted and performs no useful service.

I am aware of efforts which have heretofore been made to distort or set the lower end of the packing element first and then progressively the upper portion of the rubber by composing the lower end of the rubber of softer material than the upper end. These efforts have not proved satisfactory due among other things to the difliculty of effecting suflicient bond between the different hardnesses to withstand the high stresses of distortions of setting and retrieving the packer. In my co-pending application Serial Number 115,351, filed September 13, 1949, now Patent No. 2,660,247 issued. November 24, 1953', I have shown and claimed a packing element per se, which, with my novel packer assembly shown herein, overcomes many of the defects and failures of former packers. I herein provide a packer whereby the set first occurs at a predetermined point of the rubber by means other than compression applied to its ends, conventional end compression is resorted to only as a back-up for the initial set.

Those skilled in the art will readily perceive the many advantages of my packer from the following description together with the accompanying drawings in which:

Fig. I shows my packer assembly as being lowered into position in a well.

Fig. II shows the packer in partially set position.

Fig. III shows the packer fully set.

Fig. IV shows the packer in partially retrieved position.

In the several views, like references indicate similar parts, wherein, 5 is a well casing, 6 is a major mandrel having a threaded lower end portion 7 of smaller diameter than its body portion for engaging a collar 8 which has a shoulder 9 of larger outside diameter than the body portion of mandrel 6 for engaging with inwardly projecting shoulder ill of traveling ring 11 which in turn is threadedly engaged with metal insert 12 which is bonded to rubber packing element 13 for purposes more fully to appear later in this description. Mandrel 6 is provided with a packer seat 14 for engaging traveling ring 11. Major mandrel 6 has an axial opening 15 large enough to receive reciprocably enlarged upper end portion 16 of minor mandrel 17 and a reduced inside diameter end portion 6a large enough to receive the main body section of mandrel 17, which interfering portions of the mandrels act to limit extending movement between them and provide means whereby the minor mandrel and tail pipe as- 2,699,214 Patented Jan. 11, 1955 sembly may be lowered into and withdrawn from the well. Packing element 13 has at its lower end an insert 12a with a reinforcing collar 18 for resting on lower packer seat 19 carried by minor mandrel 17. Shear pins 20 are passed through openings in traveling ring 11 and into collar 3 whereby packing element 13 is supported while being lowered into position in the well.

The inside of packer 13 has at a point where an initial pack or set is desired of its length a portion 22 of reduced inside diameter, which diameter is sufficiently large to receive the body portion of minor mandrel 17 but smaller than collar 8 and the body portion of major mandrel 6. The rubber of the packing element at this restricted diameter Zone may be either of the same hardness as the body of the packing element or may be of different hardness. I find it facilitates the operation as herein later set out, to form this restricted portion of a somewhat harder rubber than the main body portion of the packing element.

The operation is as follows:

Before introducing the assembly into the well, minor mandrel 17 is passed through major mandrel 6 which movement is limited by the interfering portions of the mandrels above pointed out. Traveling ring 11 is passed over the mandrels and collar 8 is screwed on to the reduced end portion of mandrel 6. Packing element 13 then passed over the mandrels and the traveling ring 11 screwed on to insert 12 of the upper end of the packer and shear pins 20 driven into place. Lower packer seat 19 is now brought into position on minor mandrel 17 and anchored as by indicated threads between the parts shown in the several figures. The tail pipe assembly is engaged to mandrel 17 below the packer and the assembly lowered into the well by extensions of a supporting pipe string engaged with major mandrel 6 above packer seat 14 as shown in Fig. I. It is particularly pointed out that in this position the packer is swinging clear of lower seat 19 which feature is important and this clearance is as great as desired to accommodate the further manipulation referred to herein.

The assembly having been lowered to the point where it is desired to set the packer, the tail pipe having reached the bottom of the well or conventional slips having been manipulated through the supporting pipe string, minor mandrel 17 and packer seat 19 will have arrived at final lower limit of movement in the well.

A further lowering of the supporting pipe string lowers mandrel 6 until the packing element rests on lower seat 19. Further downward movement of the supporting string shears pins 20 and projects major mandrel 6 through the annular space between the normal inside diameter of the packing element 13 until it has reached the restricted diameter portion 22 of the packing element 13 and by reason of the thicker section of the packer wall at this point (and if preferred a harder rubber section) has distorted the latter outwardly and effected a packing engagement thereby with casing 5 as shown in Fig. II. A still further lowering of the supporting pipe string will project major mandrel 6 further through packing element 13 until upper packer seat 14 engages the traveling ring 11 and presses the upper portion of the packing element down to effect a distortion thereof to seal both the casing and mandrel 6 as shown in Fig. III. In this position any service operation desired may be carried on through the packer and the supporting pipe string such as introducing acid or cement into the well or recovering the production therefrom.

When the service operation has been completed and it is desired to retrieve the packer from the well the supporting pipe string is lifted until major mandrel 6 is pulled clear of packing element 13 until shoulder 9 of collar 8 has engaged shoulder 10 of traveling ring 11 which position provides an annular space about minor mandrel 17 into which packing element 13 may freely distort inwardly and be released from packing engagement with the casing. At this point a further upward movement of the supporting pipe string pulls on the top of packing element 13 and elongates it, freeing it progressively from the casing as shown in Fig. IV. Also as noted at this point in Fig. IV the interferences on the two mandrels have not yet engaged, thus allowing further upward movement of major mandrel 6 until packing element 13 is completely released from the casing and is swinging freely about minor manabout the mandrels between the seats, said element having a central bore adapted to freely receive the major mandrel and having a restriction in bore diameter near the end of the packer adjacent the seat on the minormandrel, the length of the major mandrel from its inner end to its packer seat being longer than the axial length ofsaid packer element and the seat on the minor mandrel being undercut axially away from said packer element adjacent the minor mandrel whereby when said mandrels telescope together the major mandrel will enter the bore and wedge under the restriction to radially expand and seat the corresponding end of the element against the well before the packer seat adjacent the other end of the element begins to longitudinally compress against said other end'of the element to expand and seat the remainder of the packer element.

2. A well packer for insertion in a pipe string comprising a major mandrel having an outwardly disposed packer seat thereon above its lower end and havingan annular enlargement at its lower end; a minor mandreltelescopically disposed below the major mandrel and having a packer seat disposed outwardly on said minor mandrel; .a resilient packer element about the packer between the seats, the lower end of the element being fixed to the lower seat and said element having a central boreradapted to freely receive the major mandrel and having an internal projection at its upper end'whereby as said major mandrel is withdrawn upwardly from within said bore said enlargement will engage said projection to forcibly elongate said element, and said element having a restriction in bore diameter near its lower end, said major mandrel being longer than the axial length of said packer element and the seat on the minor mandrel being undercut axially downwardly adjacent the minor mandrel whereby when said mandrels telescope together the major mandrel will enter the bore and wedge within the restriction to deform the lower portion of the element adjacent the restriction radially outwardly and thereby seat said portion against the well, the upper packer seat subsequentlycontacting the upper end of the element and longitudinally compressing the same downwardly.

3. A well packer comprising major and minor telescoping mandrel sectionsg'packer seats carried by the sections;

a packing element disposed about the packer between the seats and having a bore larger in diameter than the major mandrel and having a restriction in said bore of smaller diameter than said major mandrel, said restriction being near the end of the element adjacent the minor mandrel packer seat whereby said element is radially expanded upon entry therein of the major section as the major and minor sections are brought together, the seat on the major mandrel being spaced from the adjacent end of the packer element when the mandrels are elongated by a distance greater than the length of said larger bore whereby as the sections are brought together the seats begin longitudinally compressing the element after the major mandrel has wedged under said restriction.

4. A well packer comprising major and minor telescoping mandrel sections; packer seats carried by the sections; a packing element disposed about the packer between the seats and having a bore larger in diameter than the major mandrel and having a restriction in said bore of smaller diameter than said major mandrel, said restriction being near the end of the element adjacent the minor mandrel packer seat whereby said element is radially expanded upon entry therein of'the major section as the major and minor sections are brought together, the seat on the major mandrel-being spaced from the adjacent end of the packer element when the mandrels'are elongated by a distance greater than the length of said larger bore whereby as the sections are brought together the seats begin longitudinally compressing the element after the major mandrel has wedged under said restriction; and abutment means on the inner end of the major mandrel and in the end of the bore opposite the restricted end whereby said abut ment means will engage and the element will be forcibly elongated as the sections are moved apart.

References Cited in the file of this patent UNITED STATES PATENTS 56,234 Latham July 10, i866 927,874 Robinson July 13, 1909 1,422,704 Heeter July ll, l922 2,052,786 Meyer Sept. 1, 1936 2,121,051 Ragan et al. Jan. 2!, 1938 2,222,315 Jones Nov. 19, 1940 2,365,639 Holmes et a1. Dec. 19, 1944 2,426,370 Penick Aug. 26, 1947 

